As a desiccant which is sealed in a commodity package, a silica gel-containing pouch has been used conventionally, and the pouch has therein mixed cobalt chloride-impregnated silica gel which is called blue gel as an indicator used to know a dry state. But, since the cobalt is a heavy metal, a cobalt-free humidity indicator has been desired in terms of environments.
Patent Literature 1 discloses a humidity indicator which is formed of a dry molded body of a mixture of a powdery deliquescent material and a powdery color developer which develops a color by contacting with a deliquescence of the deliquescent material. But, the humidity indicator of Patent Literature 1 has a disadvantage that visibility of a color change is insufficient when humidity is increased because a pH indicator or a water-soluble pigment such as a synthetic colorant is used as a color developer.
Besides, various types of humidity indicators such as a sheet type are being demanded, and the above dry molded body cannot comply with the demands at present.    Patent Literature 1: JP-A No. Hei 7-174704